Preheat oven to 350º. Butter a shallow baking dish. Whisk together the flour and salt. In a separate bowl, whisk together the milk, lemon juice, butter, honey, Whiskey (if using), and yolks. Mix into the flour. Whip egg whites in a clean bowl on high speed until frothy. While whipping, slowly add sugar, about 1 tbsp. at a time. Whip until shiny and holds a stiff peak. Carefully fold into mixture. Pour into pan, and bake in a water bath for 45-50 minutes.